Portable fire alarm



July 16, 1957 H. B. THOMAS PORTABLE FIRE ALARM Filed Sept. 25, 1955 2Sheets-Sheet l a; w u: lzvmvrox.

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ATTOZ/VEYS July 16, 1957 THOMAS 2,799,850

PORTABLE FIRE ALARM Filed Sept. 25, 1955 @Sheets-Sheet 2 4 /Z H/5 49 /7{i h Ii 56 23 l 1 U 5 AM I *QEMFLJ 1 Ti INVENTOR.

Hf/VEY 5. 77/0/1/A 5 mum, mm' AM-44m A77'0EA/5Y5 meanse PoRrAeLE runeALARM Henry B. Thomas, Troy, N. C., assignor to Jesse Calvin Greene,Greensboro, N. C.

Application September 23, 1955, Serial No. 536,229

2 Claims. (Cl. 340-227) This invention relates to fire alarms, and moreparticularly to an improved fire alarm of the portable, battery operatedtype.

The main object of the invention is to provide a novel and improvedportable fire alarm device which is independent of the electric powerline circuit of the building in which it is employed, which is simple inconstruction, which may be easily placed in the most appropriatelocation in the building or other area to be protected against fire, andwhich is entirely automatic in operation.

A further object of the invention is to provide an improved portablefire alarm unit which is inexpensive to manufacture, which is compact insize, which is easy to adjust for operation at a predeterminedtemperature, and which is provided with means for testing the devicemanually, if so desired.

Further objects and advantages of the invention will become apparentfrom the following description and claims, and from the accompanyingdrawings, wherein:

Figure l is a front elevational view, partly in vertical cross section,of an improved portable fire alarm device constructed in accordance withthe present invention.

Figure 2 is a vertical cross sectional view taken on the line 22 ofFigure 1.

Figure 3 is an enlarged top plan view of the device taken on the line3-3 of Figure 1.

Figure 4 is a cross sectional detail view taken on the line 44 of Figure3.

Figure 5 is an enlarged cross sectional detail view taken on the line 55of Figure 1.

Referring to the drawings, the improved fire alarm device is designatedgenerally at 11 and comprises a suitable support which may consist of avertical back plate 12 to which are secured spaced horizontal cross bars13, 14, 15 and 16, as shown in Figure 2. Secured to the cross bars 13 to16 is a plate member 17 formed in its upper portion with an aperture 18shaped to receive a bell 19 and an electric motor 20. As shown in Figure2, the bell 19 is provided with an apertured top lug 21 through whichextends bolts 22 securing the bell 19 to the upper portion of plate 17at the top marginal portion of the aperture 18. Respective side blocks23 and 24 are secured to the side marginal portions of the plate 17 onopposite sides of the bell 19, as shown in Figure l.

The motor is suitably secured in the lower portion of the aperture 18and the motor shaft, shown at 25, extends rotatably through an arm 26secured to a bracket member 27 rigidly fastened to the plate 17.Designated at 28 is a horizontal cross bar which is rigidly secured toplate 17 and to the bottom edges of the side blocks 23 and 24, thetransverse cross bar 28 being recessed at its upper intermediateportion, as shown at 29, to receive the lower portion of the electricmotor 20.

Secured to the bottom marginal portion of the plate 17 is the bottomcross bar 30 which is coextensive transversely with the plate 17.Secured to the ends of the cross bar 30 and to the side edges of plate17 are the United States Patent ice respective side walls 31 and 32,said side walls being also secured to the ends of the cross bar 28 andto the respective outer side surfaces of the side blocks 23 and 24.

Thus, a rectangular enclosure 33 is defined between the cross bar 28 andthe bottom cross bar 30. Secured in said enclosure are the verticalseparator bars 34 and 35 defining three generally similar spaces shapedto receive respective batteries 36, 37 and 33, as shown in Figure 1. Asshown, the batteries 36 and 38 are upright and the intermediate battery37 is inverted. The bottom of the case of battery 38 is engaged by aterminal stud 39 threaded through the cross bar 30, said terminal studbeing connected by a suitably insulated wire 40 to one terminal of theelectric motor 20. A resilient spring contact member 41 is secured tothe cross bar 28 and engages the center contact of battery 38 at one endthereof and the end of the casing of the battery 37 at the other endthereof. A terminal screw 42 is threaded through the intermediateportion of the bottom cross bar 36 and engages the center contact ofbattery 37. A spring contact member 43 is secured to the cross bar 30and connects the terminal screw 42 to a similar terminal screw 44threaded through the cross bar 3d and engaging the bottom of the casingof the battery 36. A resilient contact spring 45 is connected to thecross bar 23 and engages the center contact or" battery 36. A suitablyinsulated wire 46 connects the spring contact 45 to a contact member 47secured to the top edge of side block 23. As shown in Figure 1, thecontact member 47 extends inwardly over the bell 19. A similar contactmember 48 is secured to the top edge of side block 24, extendinginwardly over bell 19 from the opposite side thereof with respect to thecontact member 47. A suitably insulated wire 4S connects contact member48 to the remaining terminal of the electric motor 20.

Designated at 50 is a spirally coiled bimetal thermostat spring whoseinner end is secured to a horizontally extending rod 51 which issupported in a looped bracket 52 secured to and extending upwardly fromthe side block 24. Secured to the end of the rod 51 laterally adjacentthe supporting loop of bracket 52 is a resilient arm 53. A U-shapedbracket 54 is secured to the upper portion of plate 17 adjacent the arm53. Secured to the arm 53 is a vertical upstanding stud member whichextends slidably through the respective horizontal flanges of theU-shaped bracket 54 and is provided on its top portion with a wing nut56. A coiled spring 57 surrounds the lower portion of the stud 55,bearing between the bottom fiange of bracket 54 and the arm 53, biasingthe stud 55 downwardly. By adjusting the wing nut 56 on stud 55, the arm53 may be rotated, whereby the rod 51 may be angularly adjusted, andwhereby the spirally coiled bimetal member 5%) may be similarlyangularly adjusted. Secured to the outer end of the spirally coiledbimetal member 50 is a horizontally extending contact member 58 whichextends over the ends of the contacts 47 and 4S and which is normallyslightly spaced therefrom, as shown in Figure 1. Upon a predeterminedrise in temperature, the spirally coiled bimetal member 50 flexessufiieiently to cause the contact member 53 to bridgingly engage thecontacts 47 and 48, closing the energizing circuit of the motor 20,whereby the motor is driven by the series-connected batteries 36, 37 and38. The amount of temperature rise required to cause the contact member58 to engage the stationary contacts 47 and 48 can be adjusted by theadjustment of the wing nuts 56, as above described.

Designated at 59 is a first plunger member which is slidably mounted inan angle bracket 60 secured to the top portion of plate member 17 overthe movable contact member 58, the plunger member 59 being biased up- 3r wardly' to the" position thereof shown in Figure 2 by a coiled spring'61- surrounding the shank of the plunger between the enlarged headthereof and the horizontal arm of the angle bracket 60, as shown inFigure 2. A collar upward movemenfof the plunger member 5910'-the-positron thereof shown in Figure 2'; When it is desired to cause theontact 58 to brid inglyengage the stationary contacts 47 and 48, forexample, for te'stingthe'i device, the plunger is manually'pusheddownwardly; the. end or" the: plunger acting against the movable contactmember 58, to force said movable contact member intoconte'ct 'w'ith'the"stationary contact eiem'ents' 47 and 48.

Desi nated at 64 i a generally arched bracket plate having'the lower"ortions of its legs secured to the cross 28 a's'ish'owniin Figures I and2 A pivot bolt 65 is' mounted in the top portion of" the bracketplate'64,. and rotatably mounted on the pivot boltjis' a sleeve 66, secared tothe sleeve 66 is'a relatively large gear 67 which meshes with a smallergear 68 mounted on the motor shaft25. Also secured on the sleeve 66 is'aratchet wheel 69 having trianguiar teeth 70. As shown in Fig? ure 2, theupper. portion of the ratchet whee169 projects into the lower portion ofthe bell 1 9;

Secured respectively to the sidewalls 31 and 32 are angle brackets 71and 72, and pivoted to the lower portions-of the angle brackets 71 and72, at 73' and 74 respec.- tively are the respective hammer elements 75and 76 en ageabie with o posite side po tions of the bell 19, the resective hammer elements having their shankl portions eite'ndinglthr'oughrespective bifurcated brackets 77 and 78 secured to the respective an lebrackets 71 and 72. Secured in each bracket 77 and 78 is a respectivecoiled spring79 hearing against its associated hammer member 75hr 76,biasing the hammer members inwardl namely, toward the bell 19. Securedto the res ective hammer members 75 and 76 are respective follower arms80' and 8-1 which res ectivel engage trian ular teeth on the ratchetwheel 69 at opposite sides of said ratchet wheel, asshown in Figure 1,the follower arms so ands-1' being biased downwardly by respectivecoiled springs 82- and 83 connectin the follower arms to the rossbalrZS. I

[is shown in Figure l, the follower arms 80 and 81 simultaneously engagedifferent portions or the trian ular ratchet teeth 7a at the oppositesides of the ratchet wheel 69, whereby'when the wheel 69' rotates, thefollower arms are released by the ratchet teethat different times, sothat the hammer members 75 and 76- en age the bell' 19 in sequence,rather than simultaneously.

In operation, when the temperature adjacent the device rises to a valuesuflicient to cause the thermo-responsive member 50 to move the contactelement 58 into bridging engagement with the stationary contacts 47 and48, motor 20 is energized and rotates the ratchet wheel 69, causing thehammer elements 75 and 76 to be sequentially oscillated and to strikethe bell 19 in sequence, providing a loud warning signal.

As above explained, the operating temperature of the device can beadjusted by adjusting the wing nut 56 to adjustthe normal rotatedposition of the shaft 51. Also,- as above explained, the device can betested-by depressing the plunger 59 manually, to energize the motor 20and to determine whether the device is in working condition.

While a specific embodiment of an improved portable fire alarm devicehas been disclosed inthe foregoing description, it will be understoodthat various modifications within the spirit of the invention may occurto those skilled in the art. Therefore, it is intended that nolimitations be placed on the invention except as defined by the scope ofthe appended claims.

What is claimed is:

l; A fire alarm device comprising a. support, a bell mounted on saidsupport, respective hammer elements pivoted to saids'upport' onopposite: sides of said bell and being movable 'the're'against, springmeans biasing said hammer elements against: said bell, a motor mountedon said support, a ratchet wheel. rotatably mounted on said 7 supportbetween said h'ammer'elements', means drivingly coupling said wheel tosaid motor, respective follower arms secured to said hammer elements andengaging the opposite sides of the periphery of said ratchet wheel, saidperiphery comprising successive triangular ratchet.

teeth, cliifereiit follower" arms" engaging diiferent' portions of saidteeth on the opposite sides of the ratchet'wheet, such thatthe followerarms are released by the ratchet teethlat difierent times when theratchet wh el rotates,

a battery mounted on. said support, a thermo-responsive being movablethereagainst, spring means biasing said hammer elements again'stsaid'bell, a motor mounted on said support, a.- ratchet wheelrotatably'mounted onlsaid support between said hammer elements, meanscoupling. said wheel to said motor, respective follower arms secured .tosaid hammer elements and" engaging the Opposite sides of the peripheryof said ratchet wheel, said periphery comprising? successive triangularratchet teeth, said'fbllower. arms 'engagingdifierent portions ofdilferent teeth at saidopposi't'e sides of the periphery of therat'chet"wheeI, such that the follower arms are released by the ratchet teeth at'different times when the ratchet wheel rotates, a batterymounted on saidsupport, a pair" of spaced contacts rigidly mounted on said support,circuit means connecting said spaced contacts, motor andtba't-fery inseries, a spirally coiled resilient bimetal strip disposedbetween saidspaced contacts, means securing the inner end of said" coiled bimetalstrip to said support-,Qand a conductive member secured to the outer endof said bimetal'st'rip and extending over saidspaced contacts, saidbimetal strip being flexible in response to temperature rise to movesaid conductive member into simultaneous engagement with said spacedcontacts. a

I 7 R eferences Citedin the filerof this patent t, UNITED STATESPATENTS- 7'57, 2 7r ce1 Apr; 12, 1904 1,260,461, Schuyler Mar; 26, 1918'25505673 Cufalo May 1', 195 1; zsitoie Nnceio Sept; 16,-.1952' 2,710,39?Goldberg m J'nne 7, 1 's 7 FOREIGN PATENTS 657,509 Germany Feb. 17, was

